alloc/collections/btree/
dedup_sorted_iter.rs

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1use core::iter::Peekable;
2
3/// An iterator for deduping the key of a sorted iterator.
4/// When encountering the duplicated key, only the last key-value pair is yielded.
5///
6/// Used by [`BTreeMap::bulk_build_from_sorted_iter`][1].
7///
8/// [1]: crate::collections::BTreeMap::bulk_build_from_sorted_iter
9pub(super) struct DedupSortedIter<K, V, I>
10where
11    I: Iterator<Item = (K, V)>,
12{
13    iter: Peekable<I>,
14}
15
16impl<K, V, I> DedupSortedIter<K, V, I>
17where
18    I: Iterator<Item = (K, V)>,
19{
20    pub(super) fn new(iter: I) -> Self {
21        Self { iter: iter.peekable() }
22    }
23}
24
25impl<K, V, I> Iterator for DedupSortedIter<K, V, I>
26where
27    K: Eq,
28    I: Iterator<Item = (K, V)>,
29{
30    type Item = (K, V);
31
32    fn next(&mut self) -> Option<(K, V)> {
33        loop {
34            let next = match self.iter.next() {
35                Some(next) => next,
36                None => return None,
37            };
38
39            let peeked = match self.iter.peek() {
40                Some(peeked) => peeked,
41                None => return Some(next),
42            };
43
44            if next.0 != peeked.0 {
45                return Some(next);
46            }
47        }
48    }
49}
alloc/collections/btree/dedup_sorted_iter.rs

alloc/collections/btree/
dedup_sorted_iter.rs
